exit codes from shell commands

[lmarkov]

Hello, Can you tell me how work the exit codes from shell commands? I saw that there is some kind of rewriting but may be I have mistake.

 :~# alksjdas
 -bash: alksjdas: command not found
~# echo $?
127
cd alksjdas
-bash: cd: alksjdas: No such file or directory
:~# echo $?
1
:~# nano test.txt
:~# echo $?
0

I want to filter the real shell exit codes but in python I get only 0 or 1 as a result.

[ghantoos]

I based my exit codes on some tests, but it looks like they are not the same for all commands.

Example:

~$ ls qweqwe
ls: cannot access qweqwe: No such file or directory
~$ echo $?
2

and

~$ cd qweqwe
-bash: cd: qweqwe: No such file or directory
~$ echo $?
1

I will correct the cd exit code, as well as the "command not found".

Thanks for reporting this.

[lmarkov]

Yes, there are different codes. For example: http://tldp.org/LDP/abs/html/exitcodes.html

Can you suggest how can I fix it and make exception for example when I type

# blabla
-bash: blabla: command not found
# echo $?
127

to except this error. I use additional script which creates tickets when some command or path is forbidden but I don't want to receive information for such errors every time. It could be useful this codes to be more flexible and may be to be included in the configuration files.

[ghantoos]

There is a inconsistency between bash(1) and sh(1) on the cd built-in exit code.

On sh(1):

$ cd qweqwe
sh: 5: cd: can't cd to qweqwe
$ echo $?
2

On bash(1):

~$ cd qweqwe
-bash: cd: qweqwe: No such file or directory
~$ echo $?
1

The bash documentation seems to point to an exit code of 2: http://tldp.org/LDP/abs/html/exitcodes.html

So I decided to keep the exit code provided by the python os.chdir function, for consistency.

Otherwise, I will be correcting the other exit code in my next commit.